Aquatic herbs with parallel-veined leaves and diclinous fls. on a slender-stalked spadix. Perianth regular, 3 to 6-parted, the inner segments petaloid. Stamens 3 to 12. Ovary adherent to the perianth, 1 to 9-celled, with 3. 6 or 9 large stigmas.

Fruit dry or succulent, many-seeded, indehisent. Seeds without albumen.

Genera 12. species 20. native of fresh water in Eurepe, N. America, E. Indies and N. Holland. They appear to possess no active properties.

1. LIMNO'BIUM, Richard. Frogs-bit. (Gr. a lake, life.) Flowers monoecious, arising from subsessile spathes; spathe. 1-leaved, about 3-flowered, calyx 3-sepaled, corolla 3-petaled, petals oblong-linear; stamens 6 to 12, monadelphous; spathe 2-leaved, 1-flowered; calyx and corolla as in the ; stamens 6, subulate rudiments; ovary 6 or 9-celled, becoming a co-seeded berry. - Herb acaulescent, in stagnant waters, multiplying by 6tolons, and with floating lvs. Fls. showy, white, the on long stalks.

L. Spongia Rich. - In Braddock's Bay, L. Ontario (Sartwell); scarce at the north, common in the south, E. Ky.! to Ga. (Feay) and La. (Hale). Lvs on long petioles, roundish, obtuse or broadly acute, often cordate, 1' to 18" diam. Ped. of the sterile fls. slender, about 3' long, of the fertile, thick, about 1' long, both kinds either together on the same stalk or on different stalks which are connected by the stolons (Dr. Feay). The leaves beneath are purplish and spongy with large cells. Jl., Aug. (Hydrocharis, Bosc. H. cordifoiia Nutt.)

2. ANACH'ARIS, Richard. Ditch Moss. (Gr. av, an indefinite particle, uncomely.) Flowers polygamous, solitary, from a tubular, bifid, axillary spathe; perianth 6-parted, colored; minute, with 9 oval, nearly sessile anthers; perianth excessively produced into a filiform tube above the ovary, limb 6-parted, stamens 3 to 6, often abortive; style capillary; adherent to the tube of the perianth; stigmas 3, large; fruit few-seeded. Small aquatic herbs, with submersed pellucid opposite or verticillate lvs.

A. Canadensis Planchon. Lvs. verticillate in 3s and 4s, lanceolate, oblong or linear surrulate; stig. 2-lobed. - Resembling a coarse moss, in still waters and bogs. St. filiform, diffusely dichotomous, very leafy. Lvs. 3 to 6" by (less than) 1", thin and diaphanous, sessile, obtuse. Fls. minute, of a dingy white, the slender, hair-like tube 2 to 10' long, according to the depth of the waters. Stigmas recurved between the segments, crested with glandular hairs. Aug. (Udora, Nutt.)

3. VALLISNE'RIA, Micheli. Eel-grass. (In honor of Anthony Vallisner, a French botanist.) Flowers ; spathe ovate, 2 to 4-parted. Spadix covered with minute flowers, enclosed in a 3-parted spathe; corolla 0. Spathe bifid, 1-flowered; perianth elongated; sepals linear; stigmas 3, ovate, bifid; fruit elongated, cylindrical, many-seeded. - Submersed. Lvs. all radical, grass-like. Scape spiral, very long.

V. spiralis L. Lvs. linear, obtuse, serrulate at the end, tapering at the base, floating. - A curious plant, in slow moving or stagnant waters, IT. S. Leaves linear, 1 - 2f long, about 1/2' wide, the edges thinner than the middle. Scapes several, of the sterile plants short, of the fertile plants very tortuous, 2 - 4f long when extended, thread-like, thickened at the top, bearing each a single, white flower at or near the surface. Sepals and petals crowning the (1') long, narrow, incurved ovary, which, is half concealed in the spathe. Jl, Aug. (V. Amer-icana Mx.)